Ballast block



IVU

comma R PLAsnc Patented Oct. 8, 1946 UNITED STATES Lxamme PATENT OFFICE BALLAST BLOCK Carl C. Ahles, Albany, N. Y.

No Drawing. Application May 29, 1943, Serial No. 489,257

4 Claims.

are cold molded or cast, like concrete 0 form a stron dense mass of excep o s 1 rav y.

At the present time due to the great demand for iron and steel and other heavy metals in the production of war materials, substitutes for iron pigs and the like which have been heretofore used for ship ballast, counterweights, etc., have been sought. What is needed is a material of high specific gravity which can be utilized en masse, or in the form of blocks which can be conveniently handled and closely packed and which are formed of materials not so essential in the war effort as the various heavy metals. Ordinary concrete can of course be cast en masse or in the form of blocks and for these reasons would be an ideal material were it not for its comparatively low specific gravity and the difliculty of handling and placing preformed blocks made therefrom. Copper, lead, or other heavy slags might be used in the concrete as an aggregate instead of stone, but in crushing the same, insufiicient fines are produced to use with the larger particles in order to make a dense concrete and hence, either a fine aggregate of substantially lower specific gravity, such as sand, must be used, or the expense of special fine crushing must be undertaken to produce a desirably dense concrete. Furthermore concrete blocks of such aggregate cannot be conveniently handled and are a poor substitute for iron pigs.

The principal objects of my invention are to oncrete structure having a very vi 1;, a e inmany localities an w c mre yer,

2 duces a considerable quantity of fines which may be readily separated from the lighter materials by magnetic separators. Such fines are preferably used alone with the hydraulic cement to form 5 concrete consisting en'tiflybf fine aggregate and a binder, or, as a fine aggregate mixed with a coarse aggregate of magnetite. However, a satisfactory, heavy, magnetic concrete may beformed by combining a coarse, or a partly coarse and partly fine heavyaggregate suchjfor example as or ore, which ma or may not be mag ne 10 W1 a. comparatively smmm Hr'ie myfietite. Of course the magnetic proper- 'tieso concrete will vary with the proportion of magnetic material therein but concrete in which m gnetite constitutes 10% or more, by

weight. of the total aggregate can be handled with the present types of magnetic equipment.

Because most of the lighter materials can be eliminated from the finely crushed ore and the paratively small, usually from to 40%, and the cement which is required to fill these voids, and Vvliicliis of course much lighter than the magnetite, does not reduce the specific gravity of the finished concrete to the same degree as would be 30 the case with an a gregate having a greater proportion of voids. Only suflicient water to form a workable mix should be used.

Where the material is cast in the form of blocks which must be handled or shipped, as distinguished from casting en masse, I prefer to use from four to six parts by weight of magnetite to one part by weight of hydraulic cemefit'bcause, when the magnetite ratio is appreciably increased the blocks are not so strong. If the blocks are will impafi niagfiitic t e blocks 40 subjected to Mg treatment they will, maHe'Thereirom which will facilitate W intwenty-four ours, op a crushing strength nan-w With these objects in view I have formed highly satisfactory ballast blocks from a concrete comof around three thousand pounds per square inch. Thus the blocks may be made one day and shipped the next. In twenty-eight days they will acquire prising, by weight, one part of h draulic cemen a crushing strength of about four thousand and from four to eight parts of netite. 'Eucfi blocks are highly magnetic and tfius may 5e easily handled by electromagnets. Magnetite is the magnetic oxide of iron (Fe-404) and, when pure,

contains more than 72% of metal. The specific the blocks entirely of fine aggregate anwg gravity is about 5.1. As found in nature, the magcement because by netite may be combined with lighter, non-mag netic materials and the specific gravity may vary from about 4.2 to 5.1. However, as distinguished from slags, the magnetite, when crushed, proely crus g the ore a purer and heavier concentrate is obtained, it is to be understood that both the fine aggregate and the e a ate may be magneti On the other $5, as pointed out afiafllggates of other heavy materials such, for example, as co r or lead sla s may be used with a fine ag reg e cons'fi't'ing' whole or in part'of magnetite, and blocks made therefrom will be sufficiently magnetic to permit oi their being handled by electromagnets. In any case however it should be borne in mind that a dense concrete of the heaviest materials is desired and the coarse and fine aggregate should be proportioned with this end in view so that the voids, which are necessarily filled with thecement which is very much lighter, are reduced .to a minimum.

Ballast blocks made of finely crushed magnetite and Portland cement should weigh in excess'df one un re e y pounds per cubic foot or, in other words, have a specific gravity of the order of about 3 or more; and, due to their regular size, they may be piled or packed very closely so that, when any given space is filled thereby, the aggregate weight is almost equal to that of the iron pigs which can be placed in said space.

By the term, fballast blcclr," as used in the claims, I mean to include both precast blocks of regular shape and concrete cast en masse.

What I claim is:

1. A magnetic ballast block having a specific gravity of the order 993 and up and formed of concrete comprising, by weight, about one part of hydraulic cement and from about four to about eight parts of magnetite.

2. A magnetic ballast block having a specific gravity of the order of 3 and up and formed of concrete comprising, by weight, about on part of hydraulic cement and from about six to about eight parts of magnetite.

3. The structure set forth in claim 1 in which the cement is Portland cement.

4. The structure set forth in claim 2 in which the cement is Portland cement.

CARL C. AHLES. 

